Simulated moving bed apparatus using a single sorbent bed for separating components from a fluid stream

Abstract

An apparatus and process for concentrating a selected component from a multi-component liquid using a sorbent bed having a preferential sorption rate for the selected component. The sorbent bed is enclosed in a single vessel and is operated in a simulated moving bed technique whereby the flow profile of the liquid is continually moved downwardly through the sorbent bed. Recirculation is continuous but variable and is accompanied by the injection of eluent and feedstock and the removal of extract and raffinate at preselected times, locations, and amounts as a function of the kinetics and voidage of the sorbent bed. Extract purity and operational efficiency of the sorbent bed are the result of this novel apparatus and process.

What is claimed and desired to be secured by United States Letters Patent is: 
     
       1. An apparatus for providing a simulated moving bed process to separate constituents of dissolved solids from a mixture of said dissolved solids by continuous, preferential sorption and desorption comprising: a vessel for holding a sorbent medium said sorbent medium being uniformly packed in said vessel as a stationary, noncompressible sorbent bed;   liquid distribution means comprising at least a primary distributor being located adjacent the top of said sorbent bed and a secondary distributor being located in about the middle of said sorbent bed;   liquid collection means comprising at least a primary collector being located at the bottom of said sorbent bed and a second collector being located about halfway between said secondary distributor and said primary collector in said sorbent bed;   recirculation means comprising a circulation pump and a conduit external to said sorbent bed to connect said primary collector with said primary distributor to create a loop with said circulation pump providing continuous but variable propulsion means for circulating sorbent bed liquid from said primary collector to said primary distributor and thence through said sorbent bed;   valved manifolding means for selectively introducing measured feedstock and eluent sequentially and cross-sectionally uniform into said circulating sorbent bed liquid at the top of said sorbent bed while withdrawing cross-sectionally uniform and in coordination with said feedstock and said eluent addition to said circulating sorbent bed liquid respective separated sorbed and nonsorbed fractions from said secondary distributor to maintain hydraulic balance within said loop; and   control means for selectively controlling said sorbent bed liquid, said eluent, said feedstock, and nonsorbed fraction as a function of time, the displacement volume in said sorbent bed external to said sorbent medium, the kinetics of said sorbent medium and said hydraulic balance to thereby create progressively changing concentration profiles in said circulation sorbent bed liquid through a continuous action o sorption and desorption in said sorbent bed as said circulation sorbent bed liquid passes continuously in a cross-sectionally uniform, perpendicular flow through said sorbent bed from top to bottom with said concentration profiles dynamically and repeatedly ranging from a composition containing primarily diluted nonsorbed components referred to as the displacement zone to progressively change to a mixture of all components to become nearly equivalent to said feedstock referred to as the sorption zone, followed by progressively increasing purity of a desorbed component referred to as the desorption zone, followed by a progressive decline in the total amount of said dissolved solids to a point where said circulation sorbent bed liquid is nearly equivalent to said eluent, referred to as the regeneration zone and where this pattern in said circulation sorbent bed liquid concentration is repeated and maintained through sorption, desorption, periodic addition of feedstock and eluent and coordinated withdrawal of separated fractions at steady state with each cycle.   
     
     
       2. The apparatus defined in claim 1 wherein said control means includes supply means for injecting eluent whereby said eluent is introduced through said secondary distributor to blend cross-sectionally uniform with said circulating sorbent bed liquid moving cross-sectionally uniform and perpendicular downward in said sorbent bed while said feedstock is introduced to said circulating sorbent bed liquid near said primary distributor and said desorbed component is withdrawn cross-sectionally uniform from said secondary collector. 
     
     
       3. The apparatus defined in claim 2 wherein said control means comprises selection means for introducing during a step arbitrarily chosen as first step a predetermined volume of said eluent into that part of said circulation sorbent bed liquid which is most nearly equivalent in composition to said eluent and which has previously been moved to surround said primary distributor of said sorbent bed while simultaneously withdrawing through said secondary collector and cross-sectionally uniform an equivalent volume of an optimum amount of said nonsorbed fraction from said circulation sorbent bed liquid which has previously been moved to a predetermined position all the while maintaining a controlled flowrate for the sorption characteristics of a specific sorbent bed medium, said controlled flowrate being a commensurate flowrate for said circulation sorbent bed liquid by means of said circulating pump as measured in said conduit which connects said primary collector to said primary distributor to maintain the separation between said zones and thereafter closing all inflow and outflow valves to said loop; said selection means moving immediately during a second step said circulation sorbent bed liquid by means of said circulating pump in said loop and cross-sectionally uniform downward at increased rate commensurate to kinetic properties of said sorbent bed medium and the voidage of said sorbent bed medium to maintain said steady state, dynamic concentration profile in said circulating sorbent bed liquid and said separation between said zones through said sorbent bed as said sorption and said desorption continues through said sorbent bed until the center of said sorption zone in said circulation sorbent bed liquid with a composition most nearly equivalent to said feedstock arrives at said primary distributor while at the same time moving said desorption zone in said circulation sorbent bed liquid with its optimum desorbed component purity and concentration to surround said secondary collector and moving said regeneration zone in said circulation sorbent bed liquid with a composition most nearly equivalent to said eluent to surround said secondary distributor;   said selection means injecting during a third step a predetermined volume of said feedstock to be acted upon in the shortest possible time and cross-sectionally uniform through said primary distributor into said circulating sorbent bed liquid, while simultaneously injecting a predetermined volume of said eluent cross-sectionally uniform through said secondary distributor into said circulation sorbent bed liquid all the while withdrawing cross-sectionally uniform an equivalent volume from said circulation sorbent bed liquid which contains an optimum desorbed component purity fraction through said secondary collector to maintain said hydraulic balance in said loop while maintaining said circulation sorbent bed liquid flow commensurate to the specific sorbent medium used to advance the front of said sorption zone no faster than the rate of said sorption and said desorption permits by means of said circulation pump to maintain separation of said zones at steady state, thereafter closing all inflow and outflow valves attached to said loop to proceed with a fourth step; and   said selection means repeating the conditions for said second step during said fourth step until an optimum eluent composition in said regeneration zone arrives at said primary distributor while moving at the same time said optimum nonsorbed component fraction in said circulation sorbent bed liquid to surround said secondary collector to complete the cycle and repeating said cycle in a continuous fashion.   
     
     
       4. The apparatus defined in claim 1 wherein said control means comprises a distribution means for distributing said dynamic concentration profile over more than one said sorbent bed. 
     
     
       5. The apparatus defined in claim 1 wherein said valved manifolding means includes arrangements to collect more than two said separated fractions. 
     
     
       6. The apparatus defined in claim 1 wherein said feedstock is an impure sugar solution and wherein the sorbent medium is a polystyrenic cation exchanger crosslinked with less than 10% divinylbenzene, sulfonic acid functionality, operating in the potassium form and having uniform spherical particle size of less than 450 micron. 
     
     
       7. The apparatus defined in claim 1 wherein the feedstock is a mixture of monosaccharides and wherein the sorbent medium is a polystyrenic cation exchanger crosslinked with less than 10% divinylbenzene, sulfonic acid functionality, operating in the calcium form and having a uniform spherical particle size of less than 450 micron. 
     
     
       8. The apparatus defined in claim 1 wherein the eluent is clean water free of ionic material which would interfere with the respective sorption capacity of the sorbent medium. 
     
     
       9. An apparatus for providing a simulated moving bed process to separate components from a mixture of dissolved solids in a feedstock by continuous preferential sorption and desorption comprising: a vessel for holding a sorbent medium, said sorbent medium being uniformly packed in said vessel as a stationary, noncompressible sorbent bed;   liquid distribution mans comprising at least a primary distributor being located adjacent the top of said sorbent bed and a secondary distributor being located in about the middle of said sorbent bed;   liquid collection means comprising at least a primary collector being located at the bottom of said sorbent bed and a secondary collector being located about halfway between said primary distributor adjacent the top of said sorbent bed and said secondary distributor in said sorbent bed and a third collector located about halfway between said secondary distributor in said sorbent bed and said primary collector for said sorbent bed;   recirculation means comprising a circulation pump and a conduit external to said sorbent bed to connect said primary collector with said primary distributor to create a loop with said circulation pump providing continuous but variable propulsion means for circulating sorbent bed fluid from said primary collector to said primary distributor and thence through said sorbent bed;   valved manifolding means for introducing: measured eluent cross-sectionally uniform into said circulating fluid adjacent the top of said sorbent bed; and   measured feedstock cross-sectionally uniform into said circulating fluid moving through said sorbent bed by means of said secondary distributor;     removal means for withdrawing cross-sectionally uniform and in coordination with respective said feedstock and said eluent addition to said circulating fluid the desorbed component fractions from said secondary collector and the nonsorbed component fraction from said third collector to maintain hydraulic balance within said loop;   control means for selectively controlling said feedstock, said eluent, said desorbed component fractions, said nonsorbed component fractions, and said circulating fluid as a function of time, the displacement volume in said sorbent bed external to said sorbent medium, the kinetics of said sorbent medium, and said hydraulic balance to thereby create dynamically changing but progressively moving and repeating concentration profiles in said circulation fluid through a continuous action of said sorption and said desorption in said sorbent bed as said circulation fluid passes continuously in a cross-sectionally uniform, perpendicular flow through said sorbent bed from top to bottom with said concentration profiles ranging from a composition containing primarily diluted nonsorbed components referred to as the displacement zone to progressively change to become nearly equivalent to said feedstock referred to as the sorption zone, followed by progressively increasing purity of said desorbed component fractions referred to as the desorption zone, followed by a progressive decline in total quantity of said dissolved solids to a point where said circulation fluid is nearly equivalent to said eluent, referred to as the regeneration zone and where this pattern in said circulation fluid concentration thereby established is repeated through periodic addition of feedstock and eluent and coordinated withdrawal of separated fractions at steady state with each cycle.   
     
     
       10. The apparatus defined in claim 9 wherein said control means comprises selection means for introducing cross-sectionally uniform and in the shortest possible time during a step arbitrarily designated as a first step a predetermined volume of said eluent which is commensurate to said kinetic and hydraulic properties for said sorbent medium and said sorbent bed, through said primary distributor into said circulation fluid which is in that position most nearly equivalent to said eluent from a preceding step while also introducing in the shortest possible time through said secondary distributor and cross-sectionally uniform a predetermined quantity of said feedstock fluid which is commensurate to said kinetic and hydraulic properties for said sorbent medium and said sorbent bed, into said circulation fluid which in that position is most nearly equivalent in composition to said feedstock from the preceding step, while also withdrawing a predetermined volume of separated desorbed fraction through said secondary collector cross-sectionally uniform from its optimum concentration in said circulation fluid positioned thereto in the preceding step and withdrawing all the while and cross-sectionally uniform through said third collector from said circulation fluid a measured volume of an optimum nonsorbed fraction positioned thereto in the preceding step to preserve hydraulic balance in said loop while all the time maintaining a controlled but for the specific sorbent medium and sorbent bed commensurate forward flowrate for said circulation fluid by means of said circulating pump to continue uninterrupted, forward moving action of said sorption and desorption respectively throughout said sorbent bed to maintain said dynamically changing concentration profile within said circulation fluid and separation between said zones and thereafter closing all inflow and outflow valves attached to said loop and thence proceeding immediately with a second step by; said selection means moving said circulation fluid at an increased flowrate by means of said circulating pump in said loop and cross-sectionally uniform downward flow through said sorbent bed at a rate commensurate to said kinetic and said hydraulic properties for said sorbent medium and said sorbent bed to maintain said steady state, dynamic concentration profile in said circulating fluid and the separation between said zones through said sorbent bed as said sorption and said desorption continues progressively forward throughout said sorbent bed until said dynamic concentration profile in said circulation fluid is positioned to place near eluent composition in said circulation fluid at said primary distributor, near said feedstock composition in said circulation fluid at said secondary distributor, said optimum desorbed fraction concentration in said circulation fluid at said secondary collector and said optimum nonsorbed fraction in said circulation fluid at said third collector and to repeat this pattern continuously.   
     
     
       11. The apparatus defined in claim 9 wherein said control means comprises distribution means for distributing said dynamic concentration profile over more than one said sorbent bed. 
     
     
       12. The apparatus defined in claim 9 wherein said liquid collection means includes arrangement to collect more than two said separated fractions. 
     
     
       13. The apparatus defined in claim 9 wherein said feedstock is an impure sugar solution and wherein the sorbent medium is a polystyrenic cation exchanger crosslinked with less than 10% divinylbenzene, sulfonic acid functionality, operating in the potassium form and having uniform spherical particle size of less than 450 micron. 
     
     
       14. The apparatus defined in claim 9 wherein the feedstock is a mixture of monosaccharides and wherein the sorbent medium is a polystyrenic cation exchanger crosslinked with less than 10% divinylbenzene, sulfonic acid functionality, operating in the calcium form and having a uniform spherical particle size of less than 450 micron. 
     
     
       15. The apparatus defined in claim 9 wherein the eluent is clean water free of ionic material which would interfere with the respective sorption capacity of the sorbent medium. 
     
     
       16. An apparatus for providing a simulated moving bed process to separate components form a mixture of dissolved solids by continuous preferential sorption and desorption comprising; a vessel for holding a sorbent medium said sorbent medium being uniformly packed in said vessel as a stationary, noncompressible sorbent bed;   liquid distribution means comprising at least a primary distributor being located adjacent the top of said sorbent bed and a secondary distributor being located in about the middle of said sorbent bed;   liquid collection means comprising at least a primary collector being located at the bottom of said sorbent bed, a secondary collector being located about halfway between said primary distributor for said sorbent bed and said secondary distributor in said sorbent bed and a third collector located about halfway between said secondary distributor in said sorbent bed and said primary collector for said sorbent bed;   recirculation means comprising a circulation pump and a conduit external to said sorbent bed to connect said primary collector with said primary distributor to create a loop with said circulation pump providing continuous but variable propulsion means for circulating sorbent bed fluid from said primary collector to said primary distributor and thence through said sorbent bed;   valved manifolding means for introducing: measured eluent cross-sectionally uniform into said circulating fluid moving through said sorbent bed by means of said primary distributor, said secondary distributor, said secondary collector and said third collector respectively; and   measured feedstock cross-sectionally uniform into said circulating fluid moving through said sorbent bed by means of said primary distributor, said secondary distributor, said secondary collector and said third collector respectively;     withdrawing cross-sectionally uniform from said circulating fluid measured quantities of a desorbed fraction through said primary collector, said secondary collector, said third collector and said secondary distributor and withdrawing cross-sectionally uniform measured quantities of a nonsorbed fraction from said circulating fluid through said primary collector, said secondary collector, said third collector and said secondary distributor respectively to maintain hydraulic balance within said loop;   control means for selectively controlling all of said feedstock, said eluent, said desorbed fraction, said nonsorbed fraction, and said circulation fluid as a function of time, the displacement volume in said sorbent bed external to said sorbent medium, the kinetics of said sorbent medium, and hydraulic properties for said sorbent bed to thereby create dynamic concentration profiles in said circulation fluid through continuous action of said sorption and said desorption in said sorbent bed as said circulation fluid passes continuously but at a variable rate in a cross-sectionally uniform, perpendicular flow through said sorbent bed from top to bottom with said concentration profiles dynamically and repeatedly ranging from a composition containing primarily diluted nonsorbed components, referred to as the displacement zone to dynamically change to become nearly equivalent to said feedstock referred to as the sorption zone, followed by dynamically increasing purity of said desorbed component, referred to as the desorbtion zone, followed by a progressive decline in total quantity of said dissolved solids to a point where said circulation fluid is nearly equivalent to said eluent, referred to as the regeneration zone and where this pattern in said circulation fluid concentration thusly established is repeated at steady state through periodic addition of said feedstock and said eluent, coordinated withdrawal of said desorbed fraction and said nonsorbed fraction and the dynamic action of said sorption and desorption within and throughout said sorbent bed with each cycle.   
     
     
       17. The apparatus defined in claim 16 wherein said control means comprises selection means for introducing cross-sectionally uniform and in the shortest possible time during a step arbitrarily designated as a first step a predetermined volume of said eluent which is commensurate to said kinetic and hydraulic properties for said sorbent medium and said sorbent bed, through said primary distributor into said circulation fluid which is in that position most nearly equivalent to said eluent from a preceding step, while also introducing in the shortest possible time through said secondary distributor and cross-sectionally uniform a predetermined quantity of said feedstock fluid which is commensurate to said kinetic and hydraulic properties for said sorbent medium and said sorbent bed, into said circulation fluid which in that position is most nearly equivalent in composition to said feedstock from the preceding step, while also withdrawing a predetermined volume of separated desorbed fraction through said secondary collector cross-sectionally uniform form its optimum concentration in said circulation fluid positioned thereto in the preceding step and, withdrawing all the while and cross-sectionally uniform through said third collector form said circulation fluid a measured volume of an optimum nonsorbed fraction positioned thereto in the preceding step to preserve hydraulic balance in said loop while all the time maintaining a controlled but for the specific sorbent medium and sorbent bed commensurate forward flowrate for said circulation fluid by means of said circulating pump to continue uninterrupted, forward moving action of said sorption and desorption respectively throughout said sorbent bed to maintain said dynamically changing concentration profile within said circulation fluid and separation between said zones and thereafter closing all inflow and outflow valves attached to said loop and thence proceeding immediately with a second step by; said circulation pump moving said circulation fluid at increased flowrate in said loop and cross-sectionally uniform downward flow through said sorbent bed at a rate commensurate to said kinetic and said hydraulic properties for said sorbent medium and said sorbent bed to maintain said steady state, dynamic concentration profile in said circulating fluid and the separation between said zones through said sorbent bed as said sorption and said desorption continues progressively forward throughout said sorbent bed until said dynamic concentration profile in said circulation fluid is positioned to place near eluent composition in said circulation fluid at said secondary collector, near said feedstock composition in said circulating fluid at said third collector, said optimum desorbed fraction concentration in said circulating fluid at said secondary distributor and said optimum nonsorbed fraction in said circulation fluid at said primary collector thereafter proceeding immediately with a third step;   said selection means being operable to repeat the first step as designated third step except said eluent is injected into said circulating fluid through said secondary collector only, said feedstock is injected into said circulating fluid through said third collector only, said optimum desorbed fraction in said circulating fluid is withdrawn through said secondary distributor only and said optimum nonsorbed fraction in said circulation fluid is withdrawn through said primary collector only and immediately thereafter closing all inflow and outflow valves attached to said loop manifolding to proceed immediately with the fourth step;   said selection means repeating the second step as designated fourth step until an optimum eluent concentration in said circulation fluid arrives at said secondary distributor, said equivalent feedstock composition is positioned at said primary distributor, said optimum desorbed fraction in said circulation fluid arrives at said third collector and said optimum nonsorbed fraction in said circulation fluid arrives at said secondary collector and thereafter;   said selection means repeating said first step as designated fifth step except said eluent is injected into said circulating fluid through said second distributor only, said feedstock is injected into said circulating fluid through said primary distributor only, said optimum desorbed fraction in said circulating fluid is withdrawn through said third collector only and said optimum nonsorbed fraction in said circulation fluid is withdrawn through said secondary collector only and thereafter closing all inflow and outflow valves attached to said loop to proceed immediately with the sixth step;   said selection means repeating the second step as designated sixth step until said optimum eluent composition in said circulation fluid arrives at said third collector, said optimum feedstock composition in said circulation fluid arrives at said secondary collector, said optimum desorbed fraction in said circulation fluid arrives at said primary collector and said optimum nonsorbed fraction in said circulation fluid arrives at said secondary distributor and immediately thereafter;   said selection means repeating the first step as designated seventh step except said eluent is injected into said circulating fluid through said third collector only, said feedstock is injected into said circulating fluid through said secondary collector only, said optimum desorbed fraction in said circulating fluid is withdrawn through said primary collector only and said optimum nonsorbed fraction in said circulating fluid is withdrawn through said secondary distributor only and thereafter closing all inflow and outflow vales attached to said loop to proceed immediately with the eighth step; and   repeating the second step as designated eighth step until said circulation is returned to the position identified as the beginning of the first step to repeat the cycle in a continuous fashion of steady state operation.   
     
     
       18. The apparatus defined in claim 16 wherein said liquid distribution means comprises a plurality of liquid distribution means for distributing said dynamic concentration profile over more than one said sorbent bed. 
     
     
       19. The apparatus defined in claim 16 wherein said liquid collection means includes arrangements to collect more than two said separated fractions. 
     
     
       20. The apparatus defined in claim 16 wherein said feedstock is an impure sugar solution and wherein the sorbent medium is a polystyrenic cation exchanger crosslinked with less than 10% divinylbenzene, sulfonic acid functionality operating in the potassium form and having uniform spherical particle size of less than 450 micron. 
     
     
       21. The apparatus defined in claim 16 wherein the feedstock is a mixture of monosaccharides and wherein the sorbent medium is a polystyrenic cation exchanger crosslinked with less than 10% divinylbenzene, sulfonic acid functionality, operating in the calcium form and having a uniform spherical particle size of less than 450 micron. 
     
     
       22. The apparatus defined in claim 16 wherein the eluent is clean water free of ionic material which would interfere with the respective sorption capacity of the sorbent medium.